Popular smoking articles, such as cigarettes, have a substantially cylindrical rod-shaped structure and include a charge, roll or column of smokable material, such as shredded tobacco (e.g., in cut filler form), surrounded by a paper wrapper, thereby forming a so-called “smokable rod”, “tobacco rod” or “cigarette rod.” Normally, a cigarette has a cylindrical filter element aligned in an end-to-end relationship with the tobacco rod. Preferably, a filter element comprises plasticized cellulose acetate tow circumscribed by a paper material known as “plug wrap.” Preferably, the filter element is attached to one end of the tobacco rod using a circumscribing wrapping material known as “tipping paper.” It also has become desirable to perforate the tipping material and plug wrap, in order to provide dilution of drawn mainstream smoke with ambient air. Descriptions of cigarettes and the various components thereof are set forth in Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) (1999) and U.S. Pat. No. 7,503,330 to Borschke et al, which is incorporated herein by reference. A cigarette is employed by a smoker by lighting one end thereof and burning the tobacco rod. The smoker then receives mainstream smoke into his/her mouth by drawing on the opposite end (e.g., the filter end) of the cigarette.
Certain types of cigarettes that employ carbonaceous fuel elements have been commercially marketed under the brand names “Premier” and “Eclipse” by R. J. Reynolds Tobacco Company. See, for example, those types of cigarettes described in Chemical and Biological Studies on New Cigarette Prototypes that Heat Instead of Burn Tobacco, R. J. Reynolds Tobacco Company Monograph (1988) and Inhalation Toxicology, 12:5, p. 1-58 (2000). More recently, a cigarette has been marketed in Japan by Japan Tobacco Inc. under the brand name “Steam Hot One.” It has also been suggested that the carbonaceous fuel elements of segmented types of cigarettes may incorporate ultrafine particles of metals and metal oxides. See, for example, U.S. Pat. App. Pub. No. 2005/0274390 to Banerjee et al., which is incorporated by reference herein in its entirety.
Yet other types of smoking articles, such as those types of smoking articles that generate flavored vapors by subjecting tobacco or processed tobaccos to heat produced from chemical or electrical heat sources are described in U.S. Pat. No. 5,285,798 to Banerjee et al. and U.S. Pat. No. 7,290,549 to Banerjee et al., and U.S. Pat. App. Pub. No. 2008/0092912 to Robinson et al., which are incorporated by reference herein in their entirety. One type of smoking article that has employed electrical energy to produce heat has been commercially marketed by Philip Morris Inc. under the brand name “Accord.”
Smoking articles that employ sources of heat other than tobacco cut filler to produce tobacco-flavored vapors or tobacco-flavored visible aerosols have not received widespread commercial success. However, it would be highly desirable to provide smoking articles that demonstrate the ability to provide to a smoker many of the benefits and advantages of conventional cigarette smoking, without delivering considerable quantities of incomplete combustion and pyrolysis products.